UWB Radar Signal Processing for Direction Detection in Wireless Charging
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Solution Overview
Problem
Conventional radar processing methods for detecting living objects in wireless power transfer systems are complex and suffer from analog impairments, limiting their ability to determine the direction of detected objects due to sampling at RF frequencies before down-conversion, which only allows for range and speed detection.
Innovation Solution
The implementation of digital signal processing of ultra-wide band (UWB) radar signals, involving a receiver to convert radar signals into digital signals, band-pass filtering, removing frequency content below a threshold, and down-converting to complex digital baseband signals to detect range, speed, and direction of objects in the detection area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional radar processing methods sample received radar signals at RF frequencies before down-conversion, then the system structure is simpler, but the system can only determine range or speed, not direction of detected objects
Solution Approach 1:
The patent applies preliminary action by performing digital down-conversion to complex baseband signals before digital signal processing. This preliminary conversion preserves both in-phase and quadrature components, enabling subsequent extraction of direction information alongside range and speed, thus preventing information loss before processing begins.
Solution Approach 2:
The patent changes the parameter representation by using complex baseband signals instead of simple RF samples. This parameter transformation allows the system to encode both magnitude and phase information, where phase differences between antennas can be used to determine direction, thereby resolving the limitation of only detecting range or speed.
2Ease of manufacture
If conventional radar processing methods use analog down-conversion and sampling, then the processing approach is traditional, but the system suffers from various analog impairments
Solution Approach 1:
The patent substitutes analog signal processing with digital signal processing. By performing down-conversion and filtering in the digital domain, the system eliminates analog impairments such as noise, drift, and component tolerances that affect traditional analog radar processing, thereby improving reliability while maintaining manufacturability.
Solution Approach 2:
The patent introduces complex baseband signals as an intermediary representation between RF reception and digital processing. This intermediate complex signal format preserves all necessary information while being more robust to processing errors, serving as a mediator that bridges the gap between RF reception and final detection with improved reliability.
3Loss of information
If the system uses complex digital baseband signals for processing, then direction detection is enabled, but the processing complexity increases
Solution Approach 1:
The patent segments the complex baseband processing into distinct functional stages: digital down-conversion to separate in-phase and quadrature components, followed by range processing and then direction processing using phase differences. This segmentation allows the system to manage processing complexity systematically while enabling full direction detection capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables accurate detection of range, speed, and direction of objects, overcoming the limitations of conventional methods by simplifying the processing and reducing analog impairments, thereby enhancing safety in wireless power transfer systems by effectively monitoring living objects in the vicinity.
Implementation Method 1
receive a plurality of radar signals from a radar transceiver
Implementation Method 2
convert the plurality of radar signals to a plurality of digital radar signals
Implementation Method 3
band pass filter the plurality of digital radar signals
Implementation Method 4
remove frequency content below a first threshold frequency common to at least two consecutive digital radar signals
Implementation Method 5
down-convert the plurality of digital radar signals into a plurality of complex digital baseband signals
Data Source
AI summary
An apparatus for detecting an object in a detection area of a wireless power transfer system is provided. The apparatus comprises a receiver configured to receive a plurality of radar signals from a radar transceiver. The apparatus comprises a processor configured to convert the plurality of radar signals to a plurality of digital radar signals. The processor is configured to bandpass filter the plurality of digital radar signals. The processor is configured to remove frequency content below a first threshold frequency common to at least two consecutive digital radar signals of the plurality of digital radar signals. The processor is configured to down-convert the plurality of digital radar signals into a plurality of complex digital baseband signals. The processor is configured to detect a range, a speed, and a direction of the object in the detection area based at least in part on the plurality of complex digital baseband signals.